Hey all,

The stupid search won't let me search for "3k vibration" and "3krpm vibration" returns nothing... so here goes....

I've been dealing with vibration problems in my car before I put it back on the road for the summer (Which I'd like to do very soon) (These problems got very bad at the end of last year)...
One problem may be fixed- I swapped in another driveshaft.

However, I still have a vibration at 3krpm that causes everything in the car to go nuts (think- rattling stuff in the ash tray)

I think it only does this in 3rd, 4th, 5th gear... Though it could be that I'm only noticing it there.

Any thoughts?

Thanks
~enigma32~

 

I would like to say bad engine mount (rubber broken down too much). But if its only there in 3rd, 4th, and 5th, then that can't be it. Check that anyway.

To check you mounts, just try rocking the engine by hand. There should be a fair amount of resistance to rocking the engine. If there isn't, you have a bad motor mount.

 

That's kind of along the same line I was thinking... So if I check the engine mounts Monday and that's not the problem, where should I look next?

 

*bump*

Nobody?

 

Check the driveshaft?

 

I could do that.... But I'd find it hard to believe I've had two bad driveshafts in a row....

 

The vibrationn king is back. What kind of rear end do you have? limited slip? cause if it is then you might be looking at a bad pinion gear maybe one of the teeth got cracked? What speeed does it start doing it at and does it gradually get worse or does it level off at some point?

 

It's the old fashioned simple rear end (for now...)

Seems to start at 25~30 miles and hour... at least that's where it gets noticable.
It's only really prominant around those 3krpms, but seems to do it at highway speed and non-highway speed....

 

Is the vibration there only when it is in gear and moving? Does it vibrate when in neutral and you rev. it to 3k or higher?

 

I had a fuel pump problem, or lack there of fuel, at 3000 rpm which caused the engine to shake like a mother! Just a thought.

 

Checked engine mounts-- they seem fine...
I'll check the tranny mounts soon too..

It only vibrates when I'm in gear...
However, I think there's something wrong with the clutch perhaps as well-- when I'm in neutral and idling and push the clutch in or release there's a rattling sound.

Fuel pump would be an interesting idea-- though wouldn't it also have issues when under load at higher rpms? I certainly don't have any issues opening it up goin' down the road....

Thanks for the ideas so far guys

 

Sounds like your clutch somehow got out of balance. I would say driveshaft, but that would get worse with speed. The only other thing in the driveline left to check is the clutch. Mabey you lost a counterweight (don't know how, but it is possible).

 

Progress!

I've now eliminated all the vibrations except the one that's exactly from 2800rpm - 3100rpm.

Engine mounts seem to be fine.

I have not checked the transmission mounts yet.

List of Things to Do This Weekend:
1) Check Transmission Mounts
2) Clutch?

Anything else?
Thanks again guys